OJAI, Calif. — The flames came from all sides, tearing across cliffs and roaring down mountains, burning through homes and engulfing cars. Entire communities were evacuated, forcing people to grab what they could and flee as raging wildfires spread rapidly, and in multiple directions, across Southern California.

Early Thursday, officials said that the worst of the wildfires — an enormous, fast-moving blaze known as the Thomas Fire — had surrounded Ojai, a popular winter retreat with about 8,000 residents. Most of the Ojai Valley was under a mandatory evacuation order

Yet even as they scrambled for shelter from the choking smoke and flames that turned idyllic communities into apocalyptic backdrops, many people worried about the dangers still to come. Officials warned that the wildfire threat could increase through the end of the week, with the same “red flag” weather conditions fueling the fires forecast to intensify.

The wildfires in Ventura and Los Angeles counties have so far forced tens of thousands to escape, destroying hundreds of structures and emptying homes, hospitals, schools and multimillion-dollar mansions alike.

In Ventura, the Thomas Fire burned across 90,000 acres by Wednesday night, spreading through an area larger than the city of Philadelphia. Officials there said they had evacuated more than 50,000 people from 15,000 homes, before issuing even more orders to flee.

Several areas east of the city of Santa Paula were placed under mandatory evacuation late Wednesday due to imminent danger, according to the Ventura County Sheriff’s Office.

The columns of flame began stretching toward Santa Barbara and surrounded Highway 101 — a major north-south freeway that straddles the Pacific Coast north of Ventura. The California Highway Patrol said early Thursday that it was closing a lengthy stretch of the highway, between Ventura and Carpinteria, an oceanside city in Santa Barbara County.

Los Angeles County faced comparatively smaller blazes in the Rye and Creek fires, both of which erupted Tuesday north of downtown Los Angeles.

But a new blaze, known as the Skirball Fire, began early Wednesday in Bel Air, temporarily shutting down Interstate 405 — one of the country’s busiest freeways — and forcing the evacuation of 1,200 homes across the posh hillside neighborhoods near the University of California Los Angeles campus. UCLA officials canceled classes Thursday — just two days before final exams were to begin.

Officials confronted the growing Skirball Fire while continuing to battle the Creek Fire, which had crept into the city on the other side of town.

But by late Wednesday, strong winds caused new flare-ups in the Bel Air area, Los Angeles Fire Department spokesman Peter Sanders said. Firefighters made late night water drops from helicopters in hopes of keeping the fire from jumping west of Interstate 405.

With overnight wind gusts up to 80 mph expected in some areas, Los Angeles County Fire Department Chief Daryl L. Osby issued an ominous warning Wednesday night: “It’s critically important for people that live in wildland areas that you sleep with one eye open tonight.”

Los Angeles officials said that 265 schools in the San Fernando Valley and West Los Angeles would be closed for the rest of the week as a safety measure.

“Our plan here is to try to stop this fire before it becomes something bigger,” Los Angeles Mayor Eric Garcetti (D) said at an earlier news briefing. “These are days that break your heart. But these are also days that show the resilience of our city.”

That resilience could face serious tests in coming days.

Officials in Ventura said they expected the fire to grow to the north and west over the next two days, as well as what one Cal Fire official, Tim Chavez, said was a “large probability of spot fires that will spread easily and spread rapidly.”

In Los Angeles, officials said they were bracing for another night of extremely strong winds as high as 80 miles per hour, which, combined with dry weather and parched vegetation, made the region particularly vulnerable to new fires. At an afternoon news conference, Los Angeles Fire Department Chief Ralph M. Terrazas said the winds could blow embers as far as 10 miles away. The index that the department uses to assess environmental conditions for the fire risk is at the highest level he has ever seen in his career, Terrazas said.

Los Angeles County Sheriff Jim McDonnell was one of many officials who urged residents in areas near the fires to prepare to evacuate “should the need arise.”

Not far from the Skirball Fire, residents and visitors alike were weighing whether to stay or go. Two roommates who live in the Brentwood area packed their bags and were “just hanging tight,” said one of the men, 23-year-old Wes Luttrell. Montevis Price, who was visiting Los Angeles from Miami, promptly checked out of his hotel when he saw the blaze.

“I saw the little mountain on fire and that was it,” Price said. “You can prepare for a hurricane, but you can’t prepare for something that happens all of a sudden.”

California Gov. Jerry Brown (D) declared states of emergency in Los Angeles and Ventura counties because of the fires. More than 4,000 firefighters and other first responders fanned out across the region to save lives, protect homes and evacuate residents.

Osby, the Los Angeles fire chief, said that many of the firefighters who had been working on the fire since Monday had not slept. Hundreds of other firefighters and engines were en route from Northern California and nearby states.

“You can probably understand that most of our resources are pretty tapped,” he said.

As of Wednesday evening, officials said no deaths had been recorded as a result of the blazes, but some areas that had burned were not yet accessible.

The scenes of areas around the fires in Los Angeles brought to mind the horror of a disaster film.

Day appeared as night along the coast, the smoke-masked sun casting a deep red light into the sky. Massive flames rolled down chaparral-covered cliffs toward Highway 101 from Santa Barbara south to Ventura. On the 405 highway near the J. Paul Getty Museum, videos taken from cars passing through showed a hellscape of fire and darkness: black hillsides covered in smoke and burning embers. Palm trees, a symbol of the region’s laid-back lifestyle, went up in flames.

The smoke from the fires was visible from space, according to photos taken on the International Space Station and posted by NASA.

“When you get those 40-to 50-mile-per-hour winds, the fire just rolls like a steam train and you have minutes to get to safety,” said Ventura City Councilman Erik Nasarenko.

He was in a city council meeting on Tuesday when the evacuation order came.

“It was crazy,” Nasarenko said. “In the middle of the council meeting, the city manager tells me our neighborhood is on mandatory evacuation, so I raced home, grabbed the guinea pig and the kids and bolted.”

For some, the flames had already consumed nearly everything they had.

The fire began beneath David and Theresa Brock’s house in upper Ojai around sundown Monday, jumping the road and sprinting up toward them. But a shifting wind pushed it away within a few hundred yards, and the couple believed their home of 12 years was safe. They stayed up through the night, smoke covering the grounds around them.

“I thought we were doing great, real great,” said Brock, a state-certified operator of public water systems.

At about 4 a.m. Tuesday, the winds shifted again. The fire raced toward them, covering five miles in 15 minutes. Brock turned to Theresa and said, “Let’s get outside in the dirt.” The couple keeps cattle, and the wide, grazed area outside their hilltop home acted as a natural fire break.

“At least out here,” he told her, “there’s nothing to catch fire.”

During an engineering flight test of the Cloud-Aerosol Multi-Angle Lidar (CAMAL) instrument, a view from @NASAArmstrong's ER-2 shows smoke plumes, from roughly 65,000 feet, produced by the #ThomasFire , around 1 p.m. PDT on December 5th, 2017. Photo Credit: Stu Broce pic.twitter.com/c6El8F0HJN

As the couple watched the flames approach, a transformer blew adjacent to their home, igniting a pepper tree. Sparks were sucked into their attic.

“Then we saw smoke coming out of the vent,” Brock, 57, said. “And I thought, ‘well, that’s it, we can’t save it now.’”

Brock pulled his Ford Torino and tractor out of the garage, keeping them in the fire break, and with the help of firemen, managed to pull a few items out of his house.

“But what do you take?” he said. He chose a few family photos, but the cedar chest where Theresa kept all the family documents burned.

“Then I just stood back and watched,” he said. “You see these people on TV who have lost everything, and you can’t imagine it, until it’s you. Now I am that person. I have the clothes on my back.”

A firefighter tries to keep flames from spreading while battling a wildfire in Ventura, Calif. (Noah Berger/AP)

Others felt the fear of what could come next.

“I’m scared,” said Beth Dorenkamp, a 25-year Ojai resident. “I saw the fire start at the east end of town, like a plume, but I never thought it would end up like this.”

Dorenkamp and Kathe Hanson huddled on a chilly morning at the Riverview Ranch in the Meiners Oaks neighborhood, which had been threatened but spared Tuesday as the Thomas Fire grew. The women keep horses at the ranch, and spent a mostly sleepless Tuesday night keeping watch over them.

“We all have trailers ready to go, but all of the roads are closed,” said Hanson, masked against the falling ash, holding the reins of her horse, Mozart. “So we’re sleeping in the barn and waiting to see what happens.”

Around the property, F-250s and Tundra pickups were hitched to trailers, ready to evacuate some of the 80 horses stabled there. The escape route had narrowed significantly, though, with some of the roads north into Santa Barbara County threatened by fire.

Word of mouth appeared the most common form of neighborhood newsgathering, with cell service spotty in the best of times in these high canyons, the power unstable because of the fire, and the Internet out in parts of the city.

The Carver family fled their home in Meiners Oak on Tuesday morning with flames less than half a mile from their property.

“We’d been up all night watching it,” said Cindy Carver, who with her husband, Thomas, and their two children, Caleb and Danika, moved to Ojai about eight years ago.

The family’s power had gone out, and Thomas, a ham radio operator, used a radio repeater on Sulfur Mountain as an indicator of how close the flames were and which direction they were heading. If the repeater failed, he would leave with his family. It remained active all night.

Preparations began before dawn. Thomas, a family therapist, let the turkeys, goats and chickens the family raises loose in their pens. He and Cindy grabbed the passports, a couple wedding photos, a little cash and jewelry and corralled the kids into the camper. They also grabbed Hondo and Jetta, two rescue dogs, their four cats and 10 kittens.

“There was a point where I just thought I was going to lose it, and then we all said, it’s just stuff,” Thomas said.

Caleb, 12, and Danika, 8, attend Ojai Valley School, which was closed like the others in the area. The upper campus was damaged on Tuesday, when a girl’s dormitory burned down along with several other buildings. But the students had been evacuated early, which Cindy praised.

The day off from school seemed by turns fun and frightening, given the uncertainty the afternoon and evening held. The family is keeping their camper in a parking lot, and heading home in quick visits to eat and shower.

Caleb said he was amazed that as they left home, everything around him seemed to be taking place as it did any other day — a guy riding his bicycle through the smoke, a hiker on a nearby nature preserve trail.

“How are people so normal about this?” he said.

Berman and Rosenberg reported from Washington. Noah Smith in Los Angeles; William Dauber in Van Nuys, Calif.; Travis Andrews, J. Freedom du Lac and Jason Samenow in Washington contributed to this report, which was first published on Dec. 6 and has been updated numerous times.

Scott Wilson is a senior national correspondent for The Washington Post, covering California and the west. He has previously served as The Post's national editor, chief White House correspondent, deputy assistant managing editor/foreign news and as a correspondent in Latin America and in the Middle East.